Despite combination antiretroviral therapy (ART), HIV-1 continues to form reservoirs in lymphoid, gut and central nervous system (CNS). The HIV-1 brain reservoir is a pool of long-lived cells, which include perivascular macrophages and microglia that can harbor replication-competent virus. Therapeutic interventions that can effectively eliminate HIV in these CNS cells are urgently needed. FOXO3a, a powerful transcription factor critical for aging and immune homeostasis, offers hope to eliminate HIV-1 reservoirs. Our previous publications have demonstrated that FOXO3a and cytokine TNF-related apoptosis-inducing ligand (TRAIL) target HIV-1-infected macrophages for apoptosis. Interestingly, available evidence suggests that there is a lack of FOXO3a and TRAIL signaling in the CNS cells during HIV-1 invasion. The deficiency of FOXO3a signaling and TRAIL expression may inadvertently facilitate the forming of HIV-1 brain reservoirs. Because TRAIL expression is under transcription control of FOXO3a, FOXO3a may serve as a drug target to clear HIV-1- infected macrophage and microglia during HIV-1 infection of the CNS. However, targeting FOXO3a in the CNS has not been possible due to a lack of drugs candidates. Recent drug development has provided TIC10, also known as ONC201, as a potent and stable small molecule that can activate FOXO3a and transcriptionally induce TRAIL expression. TIC10 is orally active and can cross blood-brain barrier. Moreover, TIC10 has shown efficacious antitumor effect and is currently tested in clinical trials. Therefore, we hypothesize that targetig transcription factor FOXO3a through TIC10 will induce expression of antiviral gene TRAIL and effectively eradicate HIV-1 reservoirs in the CNS. We will determine the functional effects of TIC10-mediated FOXO3a activation on HIV-1-infected macrophages and microglia. Furthermore, we will assess the therapeutic benefit of TIC10-mediated FOXO3a activation toward CNS viral load and neuroinflammation in HIV encephalitis (HIVE) and humanized mouse models. More importantly, we will determine whether the TIC10 has synergistic antiviral effect with the standard ART both in vitro and in vivo. The proposed studies will provide important proof-of-concept that endogenous FOXO3a could be harnessed to combat persistent and latent HIV-1 infection. The research strategy takes advantage of the latest drug development, the primary CNS cell cultures, the laboratory and primary live HIV-1 viral strains, and the technologies of HIVE and humanized mouse models. Understanding the interactions between immune control of HIV-1 infection and current ART will reveal new insights for the treatment of HIV-1 infection and its CNS complications.
HIV-1 brain reservoir is a pool of long lived cells primarily perivascular macrophages and microglia that persist despite treatment. This proposal is aimed at understanding a novel molecular mechanism to curtail HIV-1 persistence in the central nervous system. TIC10, a newly developed drug that activates transcription factor FOXO3a, will be investigated for its therapeutic potential to eradicate HIV-1-infected cells of the macrophage lineage.
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